1. Field of the Invention
The present invention relates to the field of electrical safety connectors. More particularly, the present invention relates to an electrical connector incorporating a locking device and a manually activated enabling switch that ensures power transfer only when the connector is locked.
2. Background of the Related Art
To prevent arcing or possible explosions, insulated cables are generally used to conduct power to systems, such as plasma processing systems, that require high power or high voltage. However, the conductors in the cables are necessarily exposed at the cable ends that connect to the power source and to the equipment to be energized. If a cable becomes disconnected at the equipment but still connected to the power source, the disconnected cable end presents a safety hazard because of the resulting exposed live conductor.
One known solution to preventing a live open end on a connecting cable generally involves a cover plate that secures the cable on a piece of equipment and a safety shut-off switch that disables a power source when the cover plate is removed. FIG. 1 is a perspective view of a cable 4 connected to a piece of equipment 7, a safety shut-off switch 2 and a cover plate 8 that activates the safety shut-off switch 2 and secures the cable 4 on the piece of equipment 7. The safety shut-off switch 2 is electrically connected to a power source (not shown) and disables the power source when the switch is in its normal position. The safety shut-off switch 2 enables the power source only when the switch is pushed to a depressed position as shown by dashed lines 2'. The cable 4, typically having protruding male connectors, is inserted into a female connector 6 disposed on the piece of equipment 7. The cover plate 8 is then mounted over the safety shut-off switch 2 and the cable 4 on the piece of equipment 7 by fasteners 9, such as a bolt or screw, to prevent the cable 4 from becoming disconnected to the piece of equipment 7 and to push the safety shut-off switch 2 to the depressed position 2' that enables engagement of the power source. When the cover plate 8 is removed from the piece of equipment 7, the safety shut-off switch 2 reverts to the normal position and disables the power source. Thus, no power is delivered through the cable 4, and no safety hazards are presented when the cable 4 is disconnected from the piece of equipment 7.
Although the above-described switching mechanism provides the desired protection, it has many drawbacks. One drawback associated with the cover plate 8 is the substantial effort and time required to position and fasten the cover plate 8 on the piece of equipment 7, particularly when a number of cables and cover plates must be attached for installation and detached for operation and maintenance of a system of equipment. The effort and time required to mount the cover plate 8 leads to a safety problem. The cumbersome nature of mounting the cover plate 8 often entices operators who work with the high voltage equipment to defeat the safety shut-off switch 2 and bypass the safety mechanism (i.e. the cover plate and the safety shut-off switch) in an effort to save time and effort. The safety-shut off switch 2 is generally easy to defeat, such as by taping the switch to hold the switch in the depressed position that enables the power source. Bypassing the safety mechanism often leads to an omission of the cover plate 8 that allows a cable 4 to easily disconnect from the piece of equipment 7 and expose a live end connector that presents a serious safety hazard.
Accordingly, there is a need for a cable connector safety device that is simple to implement and that is not easily defeated or bypassed to ensure that the safety device enables the power source only when the cable connector is locked and disables the power source when the cable connector is disconnected from the piece of equipment.